Expansion joint



R. SMlTH-JOHANNSEN EXPANSION JOINT Filed Feb; 17, 1949 IIIIIIIII\;

Irv/enter: Robert Smith-Johannsen,

y I Hi S Attorney.

Patented July 8, 1952 N'r OFFICE EXPANSION JOINT Robert Smith-Johannscn,Schenectady, N. Y., as-

signor to General Electric Company, a corpora tion of New YorkApplication February 17, 1949, Serial No. 77,043

2 Claims. 1

This invention relates to expansion joints and metal coveringscontaining such joints as, for instance, roofs, walls, etc., as well asmethods of preparing the same. More particularly, the invention isconcerned with a metal'covering comprising a series of plates havinginterlocking contacting surfaces or joints containing as packings forthe interlocking joints a flexible member comprising (1) a flexiblebacking or support and (2) a cured, solid, elastic organopolysiloxaneadhered firmly to one side of the backing,

In the manufacture of metal coverings, particularly metal roofing, ithas been the custom to interlock the contacting edges of the individualplates or shingles comprising the roof and apply to the joints somemeans for rendering the joint water-proof and, in some cases, tomaintain the flexibility of the joint in harmony with the degree ofexpansion and contraction of the individual plates due to changes intemperature caused by variation of the seasons and settling of thehouse.

The above-mentioned metallic roofs which usually compri'se eithershingles or plates of copper, tin, aluminum, etc., and recently sheetsof stainless steel, are formed by interlocking, usually by What is knownas a lock joint, sheets or shingles of the particular metal, hammeringthe joint in place and applying as a sealer for the joint, for

example, solder, tar, or other similar compositions usually employed forthe purpose. Although metal roofs have been in use for a long time, theyhave nevertheless been subject to certain disadvantages Which, up to thepresent time, have remained unsolved and which have rendered roofssubject to leakage without notice.

One disadvantage in using solder as a sealing agent for the interlockedmetallic plates or shingles is that even after the solder has beenapplied, it has often been difficult to detect small holes not closed bythe solder which, during use, permit water to enter underneath the roofwith the attendant, well-known, undesirable results. In addition,because of the unyielding characteristic of the solder, there has been aconspicuous lack of flexibility in the joints to permit easy expansionand contraction of the individual plates with variations in temperature.Because of the rigidity of such soldered joints, it has been necessaryto use thicker sections of plates and complicated expansion joints someplaces in the roof in order to overcome possible buckling of the plates.Another attempt to obviate some of the difiiculties described abovecomprised sealing the .joints between the individual plates with a tarryor resinous material which had some semblance of flexibility under thevarying expansion and contraction conditions described above. However,such sealing agents, which are usually in the nature of tars, resins,etc, are subject to the serious disadvantage that at the elevatedtemperatures to which roofs are ordinarily subjected during hot summerdays, they tend to flow and decompose with the result that theoriginalprotectionintended for such joints becomes inadequate. Inaddition, such materials at low temperatures tend to become brittle andcrack, thereby again failing in the very purpose for which they wereintended. Finally, such joints do not age Well and when exposed for longperiods of time to the eifects of sunlight, they deteriorate and crack,become brittle or peel, leaving the joint unprotected.

I have now discovered that all of the above difflculties which have beenso prevalent in the roofing art can be avoided by employing as a sealingagent or packing for the interlocked joints of the individual metalplates or shingles, a flexible tape interposed between the contactingsurfaces of the interlocked edges of adjacent metal plates comprising(1) a flexible backing and (2) a cured, solid, elasticorganopolysiloxane adhered firmly to a, side of the flexible backing,The various flexible tapes and silicone rubbers (i. e., solid, elasticorgano'polysiloxanes) which may be employed in the'practice of thisinvention are more particularly disclosed, described and claimed in mycopending applications Serial No. 77,045 and Serial No. 77,044 filedconcurrently herewith and assigned to the same assignee as the presentinvention, which applications, in order to avoid prolixity, by referenceare made a part of the instant application.

By means of my invention, I am able to obtain fiexible joints whichremain flexible at almost any temperature encountered under usual orunusual roofing conditions, which are not subject to decomposition ordeterioration by heat or cold or sun or rain, which aremoisture-resistant and Water-repellent, which do not become brittle atlow temperatures, do not flow at elevated term peratures and which, by,one of the preferred constructions of the claimed invention, serve asindicators to roofers as to whether in laying down the roof, theinterlocking joints are adequately protected to obtain the leak-proof,weatherresistant, substantially permanent roofing so long the subject ofroofing research.

in accordance with my invention, aflexible zm'ember such as'a tapeprepared according to the directions disclosed in my aforementionedcopending applications is applied around an edge or a preformed flangeof a metal sheet, and while maintained in this position the interlockingflange or joint of an adjacent metal sheet is positioned in place tocontact the free surface of the flexible tape. Thereafter, the completeassembly is hammered down in 'a manner well known in the art to yield awater-tight, heatresistant, cold-resistant, non-decomposable,essentially permanent joint.

The accompanying drawing shows the application of my claimed inventionto a simple lock joint employed in the roofing art. .'Fig. 1. is ap.er-' spective view of the flexible tape being laid in position alongone side of the flange of a metal sheet. Fig. 2, which is a side View,shows the tape being folded over the flange and a flange of an adjacentmetal sheet being positioned in place. Fig. 3 is a side view of thecomponents of Fig. 2 hammered into position showing theinterrelationship of the flange of one metal shingle with the flange ofanother shingle separated by the flexible tape, the tape being heldunder pressure bythe work-hardened metal. Fig. 4 is a detailedcross-sectional view of the elements of the sealed joint in Fig. 3.

More particularly, Fig. 1 shows a metal sheet orshingle I having aflange or fold 2 in the form of a substantially U-shaped portionpositioned in close proximity with a flexible tape 3, preferably, thoughnot essentially, containing a pressurevsensitive adhesive 4 on one sideof the tape in order to permit attachment of the tape to the side of theflange for ease in working. It is intended that the scope of theinvention contemplatesmerely placing the flexible tape free of anadhesive on the flange and bending it around so as to contact the flangeclosely in a manner shown in Fig. 2 where the flange 5 of an adjacentmetal shingle 6 has been positioned around the flexible siliconerubber-faced tape 3.

Fig. '3 discloses the individual gross elements making up a simple lockjoint after the joint has been hammered into position. The smallextension or tab 1 which extends beyond the curved end of the flangepermits visual inspection of the sealed joint to determine if all pointsalong the seam have been protected.

In Fig. 4 the whole joint is shown under compression; a greater detailof the flexible tape Bis shown, including the'silicone rubber 8, Le, thesolid, elasticorganopolysiloxane adhered on one side of a solid,flexible backing 9 (which may be,

for instance, aluminum, copper, tin, .lead, etc., sheet or foil or thinglass cloth tape, etc.) and,

in this case, the pressure-sensitive adhesive 4 covering the oppositeside of the flexible tape which permits the flexible tape to be held inplace over one flange of a metal shingle for a time suflicient to placethe flange of the adjoining sheet andhammer' it in place.

solution comprising phosphoric acid and chromiumfltrioxide maintained'ataround the boilin '20 mils thick was applied by calendering the latteronto one side of the copper foil. This tape wasthen heatedat about C.for about one hour to efiect'curing of the silicone rubber and toproduce a flexible tape in which the silicone rubber was flrmlybonded tothe copper backing.

A pressure-sensitive adhesive was then applied in the form of a verythin coating (about 1 to 2 mils) to the .uncoated side of the coppertape. Thereafter this tape was applied to the flange of a copper sheetin the manner shown in the accompanying drawing, the flange ofanadjacent copper sheet positioned around the copper tape in the samemanner as described in the aforementioned drawing and the total assemblyhammered into place using a mallet. Tests of this bond under severeweather conditions, changes in temperature and a variety of acceleratedaging tests indicated that the joint was essentially unchanged despitethe severity of the tests and that the joint was as water-tight andtemperatureresistant as when first prepared.

The foregoing general directions for making the silicone rubber-coatedcopper tape whereby a strongly adherent coating of silicone rubber tocopper foil is obtained, are moreparticularly disclosed and claimed inmy aforementioned -copending application Serial No. 77,044filedconcurrently herewith. p

Inplace-of the thin, flexible, copper foil, 'Imay also use such otherflexible backings as, for instance, aluminum, tin, lead, alloys ofthese'various metals and-of cop'peryglas's cloth or tape, etc. Moredetailed methods for-adhering thesilicone rubber to many of theseflexible backings, especially inorganic backings are more particularlydescribed in my aforementioned copending -application Serial No. 77,045filed concurrently herewi h.

The essential feature it lee-observed iri-t he practice ofmy inventionis that some suitable backing to which thesilicone rubber can headheredis employed so that reinforcdor strength- "ened silicone rubber tapesare used for the gasketing means employed herein. Althoughrexamples havebeen given above wherein only one side of the flexible" backing iscovered withsllicone rubber and the other side is covered with; apressure-sensitive adhesive, it isalso within the scope of thisinvention that both sides of the flexible backing be coated with thesilicone'rubber in the form of-a sandwich or laminate; It is conceivablethat such types of tape may beof great value,'although the generalroofing tapes which are normally employed for roofing applications needonly'be coated on one side with the 1slilicone'rubber in order to reducethe cost of the ape.

As pointed out previously, the individual metal sheets or shinglescomprising the protective surface which is bound together by theindividual lock joints containing the silicone rubber flexible tape mayalso be, for instance, aluminum, tin, stainless'z'steel, etc. In using aparticular flexible tape containing a metal as a backing with any of theaforementioned metallic sheets or shingles, caution must be exercised inthe combination of metal backing and metal shingle in accordance withthe electrochemical series to avoid corrosion or replacement of onemetal by the other.

In addition to employing my claimed invention for roofing purposes, itcan also be used in applications adapted for wall surfacings, floorings,etc., as well as in many other applications which may be suggested by areading of the disclosures of this invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. The method of making an expansible roofing joint which comprises (1)placing around a folded flange of a metal shingle a flexible tapecomprising a flexible backing to which is adhered a silicone rubber, (2)positioning the flange of another metallic shingle in close proximityaround the aforesaid flexible tape, and (3) bending the flange membersupon each other so as to compress the latter onto the resilient siliconeportion of the flexible tape.

2. The method of making an expansible roofing joint which comprises (1)placing around a folded flange of a copper shingle a flexible tapecomprising a flexible copper backing to which is adhered siliconerubber, the aforesaid flexible tape extending beyond the folded portionof the flange, (2) positioning the flange of another copper shingle inclose proximity around the aforesaid flexible tape, and (3) bending theflange members upon each other so as to compress the latter onto theresilient silicone rubber portion of the flexible tape.

ROBERT SMITH-JOHANNSEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 938,869 Hunter Nov. 2, 19091,849,869 Fischer Mar. 15, 1932 2,050,162 Creighton Aug. 4, 19362,241,058 Eason May 6, 1941

